Abutment rotary hydraulic motor or pump

ABSTRACT

A rotary abutment type hydraulic motor is disclosed comprising a housing having a rotor chamber and a pair of abutment valve chambers intersecting the rotor chamber. A rotor having at least three lobes is disposed in the rotor chamber, and a two lobed stator is provided in each of the abutment valve chambers. The abutment valve axes are circumferentially spaced apart one-half the angular spacing between adjacent rotor lobes. A unique sealing arrangement is provided between the rotor lobes and rotor chamber wherein sealing pins carried by the rotor lobes are hydraulically displaced radially outwardly to sealingly engage the inner surface of the rotor chamber during motor operation. A unique abutment valve lobe rotor hub sealing arrangement is also provided which is defined by a metal plate extending between adjacent rotor lobes and hydraulically displaceable metal pins disposed beneath the plate in recesses in the rotor hub. Hydraulic fluid under pressure biases the pins outwardly against the plate to bias the plate into sealing engagement with the abutment valve lobes during interengagement therebetween. Opposite ends of the abutment valve shafts are provided with a floating bearing and seal arrangement which is responsive to hydraulic fluid under pressure to seal the shaft ends against leakage of hydraulic fluid thereacross.

United States Patent [191 Brundage Nov.5,1974

[76] Inventor: Robert Wesley Brundage, 2809 Wakonda Dr., St. Louis, Mo.63121 [22] Filed: July 31, 1972 [21] Appl. No.: 276,662

[52] U.S. Cl 418/124, 418/139, 418/196, 418/227, 308/26, 308/36.1

[51] Int. Cl. F0lc 1/08, F01c 19/00, F03c 3/00 [58] Field of Search..418/112,113,123,124, 418/139, 196, 227; 277/94; 308/26, 36.1, 187.1

[56] References Cited 1 UNITED STATES PATENTS 927,781 8/1909 Farrow418/124 2,472,031 5/1949 Wichorek 418/77 2,487,732 11/1949 1 Schanzlin418/189 2,690,164 9/1954 418/196 2,710,581 6/1955 308/36.1 2,751,8466/1956 418/196 2,790,394 4/1957 418/1 13 3,123,012 3/1964 418/1963,416,458 12/1968 418/196 3,567,350 3/1971 Niemiec 418/112 FOREIGNPATENTS OR APPLICATIONS 1,072,674 3/1954 France 418/196 153,910 3/1956Sweden 308/36.1 469,894 b 4/1969 Switzerland 418/ 196 PrimaryExaminer-lohn J. Vrablik [57] ABSTRACT A rotary abutment type hydraulicmotor is disclosed comprising a housing having a rotor chamber and apair of abutment valve chambers intersecting the rotor chamber. A rotorhaving at least three lobes is disposed in the rotor chamber, and a twolobed stator is provided in each of theabutment valve chambers. Theabutment valve axes are circumferentially spaced apart one-half theangular spacing between adjacent rotor-lobes. A unique sealingarrangement is provided between the rotor lobes and rotor chamberwherein sealing pins carried by the rotor lobes are hydraulicallydisplaced radially outwardly to sealingly engage the inner surface ofthe rotor chamber during motor operation. A unique abutment valve loberotor hub sealing arrangement is also provided which is defined by ametal plate extending between adjacent rotor lobes and hydraulicallydisplaceable metal pins disposed beneath the plate in recesses in therotor hub. Hydraulic fluid under pressure biases the pins outwardlyagainst the plate to bias the plate into sealing engagement with theabutment valve lobes during interen'gagement therebetween. Opposite endsof the abutment valve shafts are provided with a floating bearing andseal arrangement which is responsive to hydraulic fluid under pressureto seal the shaft ends against leakage of hydraulic fluid thereacross.

18 Claims, 10 Drawing Figures PATENTEDNUV 5l974 sum 10F 4 NOV 5am I 3;PATENTED E a m 846 055 PATENTEE van? 5 1914 3. 846; 055

sum 3 a? a ABUTMENT ROTARY HYDRAULIC MOTOR R PUMP BACKGROUND In the artof positive displacement hydraulic motors of the foregoing character,the motor housing is provided with a cylindrical rotor chamber and oneor more abutment valve chambers which are cylindrical and intersect therotor chamber so as to be in fluid communication therewith. The housingis provided with fluid inlet and outlet passages opening into the rotorchamber at locations spaced about the periphery thereof. Hydraulic fluidunder pressure enters the rotor chamber through the inlet passage,imparts rotation to a lobed rotor and is discharged through the outletpassage. A lobed sealing abutment value is disposed in each of the oneor more abutment valve chambers in the housing and is adapted tosealingly engage the rotor during rotation thereof to prevent the flowof hydraulic fluid under pressure from the inlet passage to the outletpassage in a direction opposite to the direction of rotation of therotor.

Among the most difficult problems encountered in connection with theconstruction and operation of hydraulic motors of the foregoingcharacter is the fact that various fluid leakage paths exist between therotor and abutment value components and between these components and themotor housing whereby a percentage of the hydraulic fluid under pressureentering the motor through the inlet passage is ineffective as a workingfluid for driving the rotor. It will be appreciated that such losses ofworking fluid reduce the efficiency of the motor by reducing the speedat which the output shaftcan be driven. Such leakage paths exist betweenthe lobe or lobes of the rotor and the inner surface of the rotorchamber, between the interengaging surfaces of the rotor and abutmentvalve components, and in areas between the supporting shafts of thesecomponents and supporting walls of the motor housing.

Other problems encountered with regard to such hydraulic motors includethat of achieving a desired operating efficiency and torque output whilemaintaining the cost and physical size of the hydraulic motor at aminimum. Efforts heretofore to reduce the leakage problem and increaseefflciency while providing a desired torque output have resulted inmotor structures which are undesirably large and/or expensive tomanufacture as the result of the number of component parts requiredand/or the precise tolerances and close clearances with respect to theparts. In addition to the foregoing disadvantages, highly precisionedparts cause hot stalls due to unequal expansion of the parts whenheated. Also, the motor units can not tolerate overhung loads and thedistortion of parts resulting therefrom. It will be appreciated too thatthe number of parts and the precision thereof increase maintenance costsencountered when replacement of parts is required due to wear thereof.

Yet another problem encountered in hydraulic motors of the foregoingcharacter is that of achieving reasonably smooth and non-pulsingrotation of the fluid displacement component of the motor. In thisrespect, pockets of hydrualic fluid under pressure are transferred bythe displacement component from the high pressure inlet to the lowpressure outlet and, in certain motors heretofore provided, suchtransfer results in a pulsing of the output shaft through thedisplacement component. Such pulsing is caused by the sudden release ofhydraulic fluid under pressure from the moving hydraulic pockets as eachof the latter moves into communication with the outlet passage of themotor. Efforts heretofore to overcome or reduce the pulsing problemresult in an undesirably large and/or relatively expensive device due tothe design and/or number and arrangement of component parts thereof.

Furthermore, hydraulic motors have been provided heretofore which areintended primarily to provide a reasonably small motor in physicaldimension. The results of previous efforts in this direction, however,have not been as successful as desired for many reasons including thefact that the designs result in undesirably small inlet and outlet fluidpassageways, whereby the displacement capacity of the motor is reducedas well as the output torque which can be developed.

THE INVENTION in accordance with the present invention the foregoingdisadvantages and others of hydraulic motors heretofore known areadvantageously overcome.

in accordance with one important aspect of the present invention, arotary abutment hydraulic motor is provided including a rotor and a pairof abutment valves disposed within corresponding rotor and abutmentvalve chambers in the motor housing. Each abutment valve has two lobesand the abutment valves are rotatable about corresponding longitudinalaxes which are circumferentially spaced apart by an angle equal toone-half the angular spacing between adjacent rotor lobes. Thisrelationship, which will be described in greater detail hereinafter,advantageously provides for the areas of the fluid ports to be largerthan would otherwise be possible without endangering the structuralintegrity of components of the motor. In the preferred embodiment, therotor has three lobes and the abutment valves each have two lobes, whichcombination of lobes is believed novel and gives improved results. itwill be appreciated that the foregoing angular relationship provides, inthe preferred embodiment for the abutment valves to be rotatable aboutaxes which are circumferentially spaced apart 60. While the three lobedrotor and two, two lobed abutment valve arrangement is preferred for ahydraulic motor, a four lobed rotor and two, two lobed abutment valvearrangement is preferred for a pump. The latter arrangement provides,according to the above angular relationship, for the abutment valves tobe rotatable about axes circumferentially spaced apart 45 wherebyadditional fluid porting area is available within te fluid displacementchamber of the device.

In accordance with another important aspect of the present invention, asealing arrangement between the rotor lobes and the outer walls of therotor chamber is provide comprised of fluid actuated sealing elements onthe radially outer ends of the rotor lobes engagable with the walls ofthe rotor chamber during rotation.

The hydraulically actuated seal arrangement in combination with theoutlet passage operates in the manner of a valve when the correspondinglobe reaches the outlet passage, whereby hydraulic fluid under pressurein the pocket behind the lobe is gradually released for flow through theoutlet passage as opposed to being suddenly released upon movement ofthe fluid pocket into communication with the outlet passage. The gradualrelease avoids the existance of a sudden pressure drop in the fluidpocket which would result in a pulsing movement being imparted to therotor. The use per se of a hydraulically actuated sealing element on theradially outer end of a rotor lobe is not new and is disclosed inconjunction with an oscillating hydraulic motor rotor lobe in my U.S.Pat. No. 3,418,886 issued Dec. 31, 1968. The sealing arrangement of thepresent invention, however, distinguishes both structurally andfunctionally from my earlier arrangement as will become apparent fromthe description hereinafter of a preferred embodiment of the presentinvention.

In accordance with yet another important aspect of the present inventiona unique sealing arrangement is provided between the hub portions of therotor between adjacent lobes thereof and the lobes of the abutment,valve members which provides a more effective seal against fluidleakage around the hub area than heretofore possible. The sealingarrangement includes sealing elements between adjacent rotor lobes whichare hydraulically biased into engagement with the abutment valve lobesduring rotation of the rotor and abutment valve components.

In accordance with yet a further aspect of the present invention, aunique bearing and seal arrangement is provided between components ofthe housing and shaft portions of the abutment valve members toeffectively reduce leakage of hydraulic fluid across the areas betweenthe abutment valve shafts and housing. The latter sealing arrangementincludes floating bearing and sealing components associated with theabutment valve shafts and motor housing openings therefor. The bearingsare axially biased into sealing engagement with cooperable housingportions during operation of the motor and in response to hydraulicpressure thereagainst and, at times, the .force of the correspondingabutment value thereagainst. This sealing arrangement effectivelyminimizes fluid leakage along the abutment valve shafts and, moreover,advantageously lends to the economical production and maintenance of themotor by reducing the degree of accuracy required in the forming andmachining of the components of the assembly.

It will be appreciated, of course, that a rotary abutment type hydraulicmotor of the character described can be operated as a pump by drivingthe rotor shaft to transfer hydraulic fluid from the inlet to the outletpassage of the rotor chamber.

OBJECTS Accordingly, it is an outstanding object of the presentinvention to provide an improved rotary abutment type hydraulic devicecomprised of a minimum number of component parts organized to provide acompact unit which is simple to construct, inexpensive to manufacture,extremely efficient in operation and durable under conditions ofprolonged use.

A further object of the present invention is the provision of a rotaryabutment type hydraulic motor or pump which is compact in size andcomprised of component parts structured and operatively interrelated forthe device to have a higher fluid displacement capacity and torqueoutput than heretofore possible in a device of a corresponding physicalsize.

Still another object of the present invention is the provision of ahydraulic motor of the foregoing character having rotor and abutmentvalve members structured and operatively interrelated in a manner whichlends to providing a high torque output and a high volume of fluiddisplacement in a minimum amount of internal chamber space.

Still another object of the present invention is the provision of ahydraulic motor or pump having an internal sealing arrangement by whichpulsing of the fluid displacement component of the motor or pump duringoperation thereof is minimized.

A further object is the provision of a rotary abutment type hydraulicmotor or pump having a three or more lobed rotor and a pair of two lobedabutment valves and wherein the abutment valves are rotatable about axescircumferentially spaced apart by an angle equal to one-half the anglebetween adjacent lobes of the rotors.

Still another object is the provision of a rotary abutment typehydraulic motor or pump having a three lobed rotor cooperativelyassociated with a pair of two lobed abutment valves whereby torqueoutput, fluid displacement, and operating efficiency are maximized for agiven internal chamber area.

Still a further object of the present ivnention is the provision of ahydraulic motor or pump of the foregoing character in which fluidleakage internally of the motor or pump during operation thereof isminimized.

Yet another object is the provision of a hydraulic motor or pump havinghydraulically actuated seal arrangements which more effectively seal thespaces between components of the motor or pump than heretofore possible,whereby fluid leakage internally of the device during operation thereofis minimized.

Still another object is the provision of a hydraulic motor or pumphaving a lobed rotor including a unique seal arrangement comprised ofhydraulically actuated sealing pins for sealing between a lobe of therotor and the rotor chamber.

Another object is the provision of a hydraulic motor or pump of theforegoing character wherein the rotor lobe-rotor chamber sealarrangement functions to gradually intercommunicate high and low fluidpressure sides of the rotor lobes as the lobes approach the fluid outletpassages.

Yet another object is the provision of a hydraulic motor or pump havinglobed rotor and abutment valve components and including seal platesbetween the rotor lobes which plates are hydraulically biased forsealing engagement with the abutment valve lobes to prevent fluidleakage therebetween.

Still another object is the provision of a hydraulic motor or pumphaving rotor anda b utment valve components and including a uniquesealing arrangement between a shaft portion of the abutment valve and anopening in a wall of the housing in which the shaft portion is disposed,and which includes a floating bearing and sealing assembly.

PREFERRED EMBODIMENT The foregoing objects and others will in part beobvious and in part more fully pointed out hereinafter in conjunctionwith the accompanying description of the drawings which illustrate apreferred embodiment of the present invention and in which:

FIG. 1 is a perspective view of a hydraulic motor made in accordancewith the present invention;

FIG. 2 is an elevation view, in section, of the hydraulic motor, theview being along line 22 in FIG. 1;

FIG. 3 is a sectional elevation view of the motor, the section beingalong line 3-3 in FIG. 2;

FIG. 4 is a plan view of the motor, in section, the section being alongline 44 in FIG. 2;

FIG. 5 is a detail view, partially in section, of the bearing and sealarrangement between a abutment valve shaft and housing wall;

FIG. 6 is an enlarged detail view, in vertical section, of a portion ofthe rotor of the motorand illustrating the rotor lobe and rotor chamberin sealed relationship;

FIG. 6A is an enlarged detail view in vertical section illustrating therotor lobe and rotor chamber in unsealed relationship;

FIG. 6B is an enlarged detail view in vertical section illustrating therotor lobe seal element in relationship to the fluid outlet passage;

FIG. 7 is an end view of the motor, partially in section, the sectionbeing taken along line 7-7 in FIG. 3

FIG. 8 is an enlarged detail view, in vertical section, illustrating thecooperative sealing relationship between the rotor hub and a an abutmentvalve; and

FIG. 9 is a schematic cross-sectional elevation view of a hydraulic pumpmade in accordance with the present invention.

HOUSING Referring now in greater detail to the drawings wherein theshowings are for the purpose of illustrating a preferred embodiment ofthe invention only and not for the purpose of limiting the same, FIGS.1-4 illustrate a hydraulic motor, comprised of a housing includingaxially outer metal housing members I2 and 14 and an intermediate metalhousing member 16. Housing members 12 and 14 preferably, but notnecessarily, are cast aluminum, and housing member 16 preferably is castductile iron. The housing members may be interconnected in any suitablemanner and, preferably, are releasably interconnected by means of aplurality of headed studs 13. In the embodiment illustrated, for examplestuds 18 extend axially through corresponding openings in outer housingmember 14 and inner housing member 16 and into threaded engagement withcorresponding openings in outer housing member 12. Further, any suitablemeans may be provided for mounting the motor unit on a support memberand, in this respect, in the embodiment illustrated housing member 14 isprovided with integral mounting plate portions 20 each of which extendslaterally outwardly from a corresponding side of the motor housing. Eachmounting plate portion 20 is provided with a suitable opening 22 tofacilitate mounting of the motor unit to a support member therefor.

A rotor chamber 24 and a pair of abutment valve chambers 26 and 28 areprovided within the motor housing for the rotor and abutment valvecomponents of the motor to be described more fully hereinafter. In theembodiment illustrated, intermediate housing member 16 is an annularcomponent having an inner periphery contoured to provide for the rotorchamber to have a wall portion 30 having a radius of curvaturesymmetrical with respect to rotor chamber axis A. Wall portion 30 iscircumferentially symmetrical with respect to a vertical line throughaxis A in FIG. 2 and extends circumferentially a total of approximatelyRotor chamber 24 further includes wall portions 30a and 30b at oppositeends of portion 30, which portions 30a and 30b blend with thecorresponding end of portion 30 and diverge with respect to axis A forthe purpose set forth hereinafter. The inner periphery of housing member16 is also contoured to provide a pair of cylindrical surfaces 32 and 34defining the peripheral boundaries of abutment valve chambers 26 and 28,respectively. The axially opposite ends of the rotor and abutment valvechambers are defined by the corresponding inner surface faces 12a and14a of housing members 12 and 14. The inner faces of housing members l2and I4 radially outwardly of the rotor and abutment valve chambers areprovided with corresponding recesses or grooves 36 in which rubberO-ring sealing elements 38 are disposed for sealing engagement with thecorresponding opposed surface of housing member 16 when the housingmembers are interconnected. Preferably, recesses 36 follow the contourof cylindrical surfaces 30, 30a, 30b, 32 and 34 and are disposed asclose to these surfaces as is practical in order to minimize theunsealed radial surface area between the rotor and abutment valvechambers and the sealing elements.

Abutment valve chambers 26 and 28 have respective longitudinal axes Band C each of which is parallel to and equally spaced from thelongitudinal axis A of the rotor chamber. Further, in the embodimentillustrated, abutment valve chamber axes B and C are circumferentiallyspaced apart 60.

ROTOR A rotor member 40, preferably of powdered iron, is disposed inrotor chamber 24 for rotation about axis A and is keyed or otherwisemounted on a shaft 42 or rotation therewith. Rotor 40 preferably is ofan axial length less than the axial thickness of housing member 16 byapproximately 0.001 inch per inch of length, whereby a clearance space41 ia provided between each end of the rotor and the correspondingsurface of housing members 12 and 14. Shaft 42 preferably is of hardenedsteel and extends axially through chamber 24 and through correspondingshaft openings in housing members 12 and I4. Bearings 44 are providedbetween shaft 42 and the shaft openings in housing members 12 and 14 tosupport shaft 42 and thus rotor 40 for rotation about axis A. One end 46of shaft 42 extends axially outwardly of housing member 14 to define anoutput shaft for the motor. A thrust bearing assembly 48 is disposed ina recess in the outer face of housing member 14 and surrounds shaft 42to limit axial displacement thereof relative to the housing. In thisrespect, the inner race of bearing race of bearing assembly 48 issupported by shaft 46 and is positioned axially thereof by splitretainer rings 50 disposed in corresponding peripheral recesses in theshaft. Bearing assembly 48 is removably retained in place by means ofrings 50 and an end plate 52 mounted on the outer face of housing member14 such as by threaded fasteners 54 tending through openings in plate 52and into housing member 14. A seal assembly 56 surrounds shaft portion46 and may, for example, be defined by an annular sealing component 58biased radially inwardly for sealing engagement with shaft portion 46 bya coil spring 60 extending thereabout and in engagement therewith. Sealassembly 56 seals the motor against leakage of hydraulic fluid axiallyoutwardly along shaft portion 46 at the corresponding end of the motor.

The end of shaft 42 opposite end 46 thereof terminates in a gear chamber62 defined by a recess in the outer end face of housing member 12, whichrecess is closed by a suitable metal end plate 64 mounted on housingmember 12 such as by means of threaded fasteners 66. The latter end ofshaft 42 is provided with a gear 68 which is mounted on the shaft forrotation therewith in any suitable manner. In the embodimentillustrated, gear 68 is mounted on the shaft by means of a key 70, andaxial displacement of gear 68 relative to the shaft is restrained by apair of split retaining rings 72 having portions disposed incorresponding peripheral recesses in the shaft. The purpose andoperation of gear 68 will be described more fully hereinafter.

ABUTMENT VALVES Abutment valve members 74 and 76 are disposed inabutment valve chambers 26 and 28, respectively. Abutment valves 74 and76 are of identical construction and are similarly supported forrotation relative to the motor housing. In this respect, with referenceto abutment valve 74 illustrated in FIG. 3 of the drawing, the abutmentvalve has a shaft portion 78, preferably of hardened steel, extendingaxially from one end thereof into a corresponding shaft recess 80 inhousing member 14. A suitable bearing 82 is disposed between shaftportion 78 and the inner surface of recess 80 to support thecorresponding end of the abutment valve for rotation relative to thehousing. Further, shaft portion 78 includes a terminal shaft portion 84extending axially from the outer end thereof and into a correspondingrecess 86 extending axially from recess 80. Terminal shaft portion 84 isof a smaller diameter than shaft portion 78 and a bearing and sealingassembly 88 to be described more fully hereinafter is provided betweenshaft portions 78 and 84, the end face of recess 80 and the peripheralwall of recess 86. Similarly, abutment valve 74 is provided with ahardened steel shaft portion 90 extending axially from the opposite endthereof into a corresponding recess 92 in housing member 12. A bearing94 similar to bearing 82 is provided between shaft portion 90 and recess92 to support the shaft portion for rotation relative to the motorhousing. Shaft portion 90 has a terminal shaft portion 96 extendingaxially outwardly therefrom and through a housing wall portion 98 intogear chamber 62. Shaft portion 96 is of a diameter corresponding to thatof shaft portion 84 and is also provided with a seal assembly 88 which,in this instance, is disposed between shaft portions 90 and 96, theinner face of housing wall 98 and the inner surface of the opening inwall 98 through which shaft portion 96 extends. The outer end of shaftportion 96 is provided with a gear 100 which is keyed or otherwisemounted on shaft portion 96 to prevent relative rotation therebetween.Further, gear 100 is axially positioned relative to the shaft portion bya pair of split rings 102 having inner portions associated withperipheral grooves in the shaft portion in a well known manner. Theteeth of gear are disposed in meshing engagement with the teeth of gear68 of the rotor shaft as can readily be seen in FIGS. 3 and 7. Likewise,the corresponding gear 100 mounted on the corresponding terminal shaftportion of abutment valve 76 is disposed in meshing engagement withrotor shaft gear 68.

The assembly abutment valve comprised of the body portion of theabutment valve disposed in the abutment valve chamber and the shaftportions extending from axially opposite ends thereof, may be anintegral unit, but preferably, the shaft portions including the terminalshaft portions are produced as integral components separate from theabutment valve body and are suitably interconnected with thecorresponding end of the abutment valve body such as by brazing. Theabutment valve body preferably is of hardened steel.

ROTOR-ABUTMENT VALVE RELATIONSHIP Referring now in greater detail to thestructures and the cooperative operational interrelationship between therotor and abutment valves components, it will be seen in FIG. 2 thatrotor 40 is comprised of a cylindrical hub portion and three radiallyextending rotor lobes 112a, ll2b and 1120 equally spaced apart about theperiphery of the hub portion. The rotor lobes extend radially from thehub portion and terminate in corresponding outer faces 114 generallyparallel to and slightly spaced inwardly of inner surface 30 of therotor chamber, as best seen in FIGS. 2 and 6. Further, thecircumferentially opposite sides of each rotor converge in the directionfrom the rotor hub toward outer faces 114.

The body portions of abutment valves 74 and 76 are of identicalstructure and, accordingly, it is only necessary to describe thestructure of one of the abutment valve bodies in detail. In thisrespect, with reference to FIG. 2 it will be seen that abutment valve 76includes an opposed pair of lobes 116a and 1161) and an opposed pair ofrecesses 118. Recesses 118 preferably are cylindrical in cross sectionand are of an axial length slightly greater than the axial thickness ofhousing member 16. Further, the recesses have a radius providing a depthrelative to axis C which will provide for rotor lobes 112a, ll2b and112C to pass therethrough free of interengagement therewith duringrelative rotation of the rotor and abutment valves as set forth morefully hereinafter. The portion of the abutment valve body betweenrecesses 118 defines the pair of diametrically opposed abutment valvelobes 116a and 1161;. Each of the abutment valve lobes has a cylindricalouter surface 120 cooperatively engagable with the rotor hub in the areathereof between peripherally adjacent rotor lobes 112 in the mannerdescribed hereinafter. Further, the cylindrical outer surfaces 120 ofthe abutment valve lobes are adapted to sealingly engage cylindricalsurface 34 of the abutment valves chamber during rotation of theabutment valve.

The three lobe rotor and two lobe abutment valve arrangementadvantageously provides for applicants device to be of compactconstruction, for the components thereof to be structurally sound, andfor the device when operated as a hydraulic motor to have a high torqueoutput and maximum volumetric fluid displacement. In this respect, withreference in particular to FIG. 2, the structure and arrangement ofthese components facilitates providing the rotor chamber with fluidinlet and outlet passages 122 and 124, respectively, having a largerarea then would be otherwise possible, whereby the maximum volume offluid flow through the device is achieved. The area of the inlet andoutlet openings in a device of this character is determined in part bythe circumferential space available in the rotor chamber which in turnis determined in part by the diameter and circumferential positioning ofthe abutment valves. The size of the abutment valves in turn isdetermined in part by strength requirements therefor to assure againststructural failure. By employing a rotor having three lobes and a pairof abutment valves each having two lobes, in accordance with the presentinvention, the abutment valves are structurally sound and minimize thecircumferential space relative to the rotor axis which is necessary tohouse the abutment valve components. More particularly, the abutmentvalve components are each two-thirds the diameter of the rotor hub andare physically located approximately 60 apart from one another, thelimitation to closeness being that they must be separated byapproximately one-half the angle between two adjacent rotor lobes.

In the embodiment illustrated, as mentioned hereinabove, the abutmentvalve axes B and C are advantageously circumferentially spaced apart 60.The provision of two two-lobed abutment valves so related physicallywithin the housing increases the circumferential area available todefine the rotor chamber within the housing. This in turn increases thesize of the inlet and outlet openings which can be employed. In thisrespect, it will be appreciated that the three equally spaced lobes ofthe rotor have radial axes circumferentially spaced apart 120 relativeto one another. This distance between the rotor lobe axes determines thecircumferential distance which can exist between end 122a of inlet port122 and end 124a of outlet portion 124 so that the fluid pocket definedbetween two circumferentially adjacent rotor lobes is closed to fluidflow through inlet 1122 an instant before the pocket moves intocommunication with outlet passage 24 for the fluid to flow from thepocket through the outlet. The circumferential distance between ends122a and 12b of inlet passage 122 and ends 124a and 1241b of outletpassage 124 is limited only by the circumferential surface areaavailable in housing member 12 through which the ports open between ends122a and l24a and the point along the surface of housing member 12 atwhich the opposite port edge would intersect with the outer surface ofthe corresponding abutment valve. With the two abutment valvesarrangement in which the abutment valve axes are spaced 60 from oneanother, as illustrated in FIG. 2, the inlet and outlet ports can have acircumferential extent between the circumferentially opposite endsthereof in excess of 60. The radial dimension of the inlet and outletports is limited only by the radial space existing between the hubportion of the rotor and the peripheral surface 30 of the rotor chamber.Accordingly, reasonably large port areas are achieved whereby a highvolume of fluid displacement through the device is made possible. Thedisplacement capabilities of the device are also enhanced by the threelobe two lobe concept in that the rotor lobes can project radially fromthe hub portion of the rotor to an extent which provides a maximumvolume for the fluid pocket defined between circumferentially adjacentrotor lobes and the inner surface of the rotor chamber for given hub andabutment valve diameters.

OPERATION During operation of the hydraulic motor, hydraulic fluid underpressure enters the rotor chamber through inlet port 122 and impartsrotation to the rotor in a counter-clockwise direction as viewed in FIG.2. Rotation of rotor 30 drives rotor gear 68, whereby abutment valvegears are driven simultaneously and in a direction opposite that of thedirection of rotation of the rotor, whereby abutment valves 74 and 76are rotated clockwise as viewed in FIG. 2. The rotor and abutment valvesare operatively interrelated with the corresponding chambers within thehousing and with one another so that peripherally adjacent rotor lobescooperate with inner surface 30 of the rotor chamber and the end wallsof the chamber to define a sealed moving pocket by which the hydraulicdrive fluid is transferred from the inlet to the outlet port. Moreover,the radially outer surface of the lobes of the abutment valves sealinglyengage the rotor in the hub areas thereof between adjacent rotor lobesto seal against fluid leakage around the hub in a direction opposite thedirection of rotation of the rotor. Heretofore, sealing against fluidleakage from the high pressure side of a rotor lobe to the low pressureside thereof has been achieved in various ways including precisionmachining of the outer end of the rotor lobe and inner surface of therotor chamber, or the use of a resilient or fibrous sealing elementcarried by the rotor lobe and engagable with the peripheral surface ofthe rotor chamber. Further, sealing engagement between an abutment valvelobe and the rotor hub to reduce leakage of high pressure fluidthereacross has been achieved generally by precision machining of thestator and hub surfaces. Such machining operations are extremelyexpensive and time consuming and thus add considerably to the cost ofproduction. Moreover, machined sealing surfaces do not provide thedegree of sealing engagement required to achieve effective sealing,whereby an undesirable amount of leakage exists even when the machiningis extremely precise. Further, although theoretically frictionless evenunder heavy loading, in practice these surfaces can not be held incomplete sealing engagement at different temperatures.

The provision of flexible or resilient sealing elements in the spacebetween the rotor lobes and rotor chamber is undesirable in that suchelements are structurally weak and have poor wear characteristics,whereby they are subject to damage and deterioration requiring frequentreplacement thereof.

ROTOR LOBE SEAL In accordance with another aspect of the presentinvention, sealing against fluid leakage across a rotor lobe is achievedby a unique seal arrangement which is extremely effective in reducingthe amount of leakage heretofore experienced. More particularly, eachrotor lobe 112a, lll2b and M20 is provided with a correspondinglongitudinally extending dovetailed recess 126 opening inwardly of outersurface 114, as is best illustrated in FIGS. 6 and 6A of the drawingdepicting the arrangement in conjunction with rotor lobe 112C. Recess1126 is longitudinally coextensive with the rotor lobe 112C and isdefined by a pair of opposed side walls 128 and I30 which divergerelative to one another in the direction from surface 114 towards rotoraxis A. The recess further includes a bottom wall defined by opposedbottom wall portions 132 and 133 extending inwardly of the recess fromthe corresponding side walls 128 and 130. Bottom wall portions 132 and133 extend at an angle relative to one another and intersect along alongitudinal line extending generally centrally of the recess.Preferably, recess 126 is provided in the lobe by making the rotor ofpowdered metal in a die which has the desired recess contour. It will beappreciated, however, that the rotor can be otherwise produced and therecess provided therein in any suitable manner.

A sealing element 134, preferably in the form of a hardened steel pin,is disposed in recess 126 and is of a length longitudinally coextensivewith the recess. Preferably, the pin is of solid cylindricalconstruction and is of a diameter slightly greater than thecircumferential space between the outermost edges of side walls 128 and130 of recess 126. Moreover, for the reason pointed out hereinafter, thediameter of pin 134 is such that a portion of the pin designated 134a inFIG. 6A, projects radially outwardly of outer surfaces 114 of the recesswhen the pin is disposed in engagement with bottom wall portions 132 and133. Further, outer surface 114 is spaced from inner surface 30 of therotor chamber to define clearance space 136 which has a radial dimensiongreater than the distance pin portion 134a extends beyond lobe surface114. Clearance space 136 together with the dimensional relationshipbetween pin 134 and recess 126 provides for a fluid inlet passage 138 toexist between pin 134 and recess wall 130 when the pin is displacedoutwardly of the recess to engage inner surface 30 of the rotor chamberas illustrated in FIG. 6. The radial dimension of clearance space 136may vary, as may the size of the pin and the circumferential distancebetween the outer edges of walls 128 and 130, so long as fluid underpressure behind the rotor lobe can enter recess 126 between the pin andrecess wall 130. Fluid under pressure entering the recess in this mannerdisplaces pin 134 both radially outwardly and circumferentially intoline contact with recess wall 128 and chamber surface 30. It will beappreciated, that many recess configurations could be provided tosupport the pin for engagement with the chamber surface and a wall ofthe recess in this manner; however, to be low in friction the includedangle between the dovetail sides should be at least 15.

In operation of the pin and recess sealing arrangement, when one of therotor lobes moves past end 122a of inlet passage 122 during rotation ofthe rotor, hydraulic fluid under pressure from the inlet passage flowsthrough clearance space 136 and into pin recess 126 through passage 138.The high pressure fluid also flows through the restriction defined bythe space between pin portion 134a and chamber wall 30, whereby apressure drop exists on opposite sides of the pin tending to pull thepin outwardly of recess 126. This pressure drop together with highpressure fluid entering recess 126 through passage 138 displaces pin 134outwardly and circumferentially as described hereinabove.

The trailing end of the fluid pocket ahead of the one rotor lobe is thusimmediately sealed and the leading end of the pocket communicates withoutlet pasaage 124 releasing the fluid in the pocket for flow throughthe outlet passage. Therefore, the fluid pressure in the pocket ahead ofthe one rotor lobe is reduced and a pressure drop exists across the onerotor lobe. The pressure drop provides for the high pressure fluidadjacent the back side of the one rotor lobe to exert a force on pin 134from within pin recess 126 which is operable to maintain the pin intight sealing engagement with chamber surface 30 and recess wall 128. Itwill be noted that the pressure of the hydraulic fluid is exerted alongthe entire length of the pin and circumferentially thereof to an extentwell in excess of in the embodiment illustrated, thus to partially lowerthe force and hence the sliding friction between the pin and thedovetailed face. It will be further noted that pin 134 is free to rotaterelative to recess 126 and in response to movement of the rotor loberelative to surface 30, thus to provide for uniform wear of the pinsurface and retention of the cylindrical contour thereof both to prolongpin life and to maintain sealing efficiency.

As mentioned hereinbefore with regard to rotor chamber 24, surfaceportions 30a and 30b of the chamber blend with the corresponding ends ofsurface portion 30 and diverge with respect to chamber axis A. The freeends of surface portions 300 and 30b are spaced from axis A a distancesufficient to provide for pins 134 to be spaced therefrom whenthe pinsare in their radially outermost positions in the corresponding loberecess 126. The circumferential portions of surfaces 30a and 30b betweenthe free ends thereof and the corresponding end of surface portion 30provide for the spaced relationship to be maintained so that the pin ofa lobe approaching inlet port 122 will not sealingly engage the chambersurface ahead of the port and thus deadhead the unit. Further, portions300 and 30b of the rotor chamber surface provide for a pin 134 to begradually pushed radially inwardly of its dovetailed recess 126 as thecorresponding lobe approaches surface portion 30, and define atransitional area in the approach to surface portion 30 in whichspinning or rotation of a stationary lobe pis is initiated. Further, aspin 134 approaches the outlet passage, the pin gradually moves radiallyoutwardly as it moves onto surface 30b which has a larger radius thansurface 30. This decompresses the high pressure fluid before it isexposed to the lower pressure outlet port. FIG. 6B shows an alternate oradditional method of decompression by having the bottom of thedovetail-sealing pin groove gradually communicate with the outlet port.

As further mentioned hereinabove, recesses 118 of abutment valves 74 and76 are of an axial length slightly greater than the axial thickness ofhousing member 16. It will be appreciated, therefore, that when a rotorlobe is disposed in an abutment valve recess 118, the corresponding lobepin 134 can move axially of the recess so that one end of the pin ispositioned axially beyond the plane of the inner surface of thecorresponding one of the housing members 12 and 14. To assure that thepin is displaced axially back into the housing as the rotor lobe leavesthe abutment valve recess, tapered lead-in recesses 119 are provided inhousing members 12 and 14 on circumferentially opposite sides ofabutment valve chambers 26 and 28. Each recess 119 is radially spacedfrom rotor chamber axis A a distance corresponding to the radialposition of a lobe pin 134 relative to axis A so that the pin end willengage the tapered recess surface and be pushed axially inwardly of thehousing as the rotor rotates.

FLUID PRESSURE VALVING IN ROTOR CHAMBER As is best seen in FIGS. 2 and 4of the drawing, the axis of inlet passageway 122 opens longitudinallyinto the rotor chamber from housing member 12. Housing member 12 isprovided with a laterally extending fluid passage 140 connectable to asource of hydraulic fluid under pressure and having an inner end influid communication with inlet passage 122. Further, housing member 14is provided with a longitudinally extending recess 144 located axiallyopposite and in alignment with inlet passage 122, whereby the hydraulicfluid entering the rotor chamber flows axially into recess 144 toprovide for a uniform distribution of fluid pressure across the trailingface of a rotor lobe moving past the inlet passage. Similarly, fluidoutlet passage 124 opens longitudinally into the rotor chamber fromhousing member 12, and a laterally extending outlet passage 146 isprovided in housing member 12 which opens laterally into passage 124.Passage 146 is connectable to a line or conduit for returning thehydraulic fluid to the sump or other source from which the fluid issupplied. Housing member 141 is provided with a recess 14% axiallyopposite and in alignment with outlet passage 124 to provide for aportion of the fluid released from a pocket behind a given rotor lobe tospread longitudinally and in a direction opposite to that of the outletpassage to assure maintaining a balanced force condition on the rotorduring operation thereof.

In addition to the sealing function provided by the pin and recessarrangement described hereinabove for the rotor lobes, the pin andrecess structure provides a valving function operable to graduallyrelease high pressure fluid from a fluid pocket when the rotor lobedefining the forward end of the pocket reaches the outlet passage. Moreparticularly, as illustrated in FIG. 68, when a rotor lobe such as lobe112C, for example, approaches outlet passage 12 1 the portion of loberecess 126 filled with hydraulic fluid under pressure moves intocommunication with end 12411 of the outlet passage before rear wall 113of the lobe reaches end 124a of the passage. Accordingly, at the instantrecess 126 communicates with outlet passage end 1240 fluid underpressure in the recess is released to flow into the outlet passagewayestablishing a pressure drop between the fluid pocket behind the rotorlobe and recess 126. This pressure drop causes fluid under pressurebehind lobe 112C to flow through clearance space 136 and fluid passage138 into recess 126 and thence into outlet passage 124. Fluid flow inthis manner provides an initial flow of high pressure fluid into theoutlet passageway reducing the pressure in the fluid pocket behind rotor112e, whereby when rear face 113 of the lobe communicates with theoutlet passage there has been an initial drop of pressure in the pocketto substantially lessen pulsing movement of the rotor which would resultfrom sudden direct communication of the fluid pocket with the outletpassage. It will be appreciated that recess 148 in housing member 14opposite outlet passageway 124 has a peripheral contour corresponding tothat of outlet passage 124 so that the valving action operates torelease fluid under pressure in axially opposite directions relative tothe lobe recess for the purpose of maintaining balanced force conditionson the rotor.

ROTOR HUB-ABUTMENT VALVE SEAL With reference now to the sealingengagement relationship between the hub portion of the rotor and thelobes of the abutment valves, reference is made to FIGS. 2 and 8 of thedrawing. The areas of hub portion of rotor 11) which extend betweencircumferentially adjacent ones of the rotor lobes 112a, 112b and 1120are each provided with a corresponding hydraulic fluid actuated sealarrangement designated generally by the numeral 150. The sealarrangements in the rotor hub areas and the cooperative sealingengagement of the abutment valve lobes therewith are identical and,accordingly, only one will be described in detail, namely thatassociated with rotor lobes 112a and 111%. Sea] arrangement is definedby a seal plate 152 longitudinally coextensive with the rotor chamberahd having circumferentially opposite ends 154 and 156 loosely disposedin corresponding slots provided in the radially inner or root ends ofrotor lobes 112a and 112i). Preferably, plates 152 are steel platesformed to an arcuate contour to provide an arcuate outer surface 158engagable with cylindrical outer surfaces 120 of the abutment valvelobes. in the illustration in FIG. 8, lobe surface 120 of lobe 1160 ofabutment valve 76 is depicted.

Plate 152 is provided with a plurality of openings 162a-g extendingtherethrough for the purpose set forth more fully hereinafter. Further,the hub portion between rotor lobes 112a and 11212 is provided with aplurality of recesses 164a-f numbering one less than plate openings162a-g and which are longituidnally coextensive with the rotor and openradially outwardly behind plate 152. For the purpose set forth morefully hereinafter, the longitudinally extending side walls of eachrecess 164a-f preferably are inclined to converge in the direction fromthe outer open ends thereof towards the bottom thereof. However, therecesses could be otherwise contoured in cross section. Adjacent ones ofthe recesses 164a-f are spaced apart by a tooth-like radial projection168 having an outer face 170 radially spaced from the inner surface ofplate 152. Such spacing provides for circumferential communicatonbetween adjacent recesses. Each recess is provided with a radiallydisplaceable fluid pressure applicator 166, preferably in the form of acylindrical hardened steel pin which is longitudinally coextensive withthe corresponding recess. Each pin is adapted to engage and exert aforce against a corresponding overlying portion of plate 152 to displacethe plate radially outwardly of the rotor axis and against cylindricalouter surface 120 of the abutment valve as set forth hereinafter.

Openings 162ag in plate 152 define fluid passages for communicatingrecesses 16411-1 with fluid in the area between plate 152 and abutmentvalve 76 and are equidistant between the seal pins 166. End openings162a and 162g are in the form of slots so as to permit movement of plateends 154 and 156 inwardly of their corresponding support slots withoutclosing the passages. The remaining openings preferably are circularapertures. The several openings are illustrated in FIG. 4 as beingdisposed in a row extending substantially centrally of thelongitudinally opposite ends of the plate. It will be apparent from thedescription hereinafter, however, that the contours of the openings aswell as the disposition thereof can be varied without departing from oraffecting the purpose and operation thereof. Openings 162b-f are eachdisposed in overlying realtionship with a projection 168 betweenadjacent recesses in the hub. Further, openings 162b-f each have adimension in the circumferential direction which provides for theopening to be closed by covering engagement of abutment valve surface120 therewith, for the purpose set forth below.

During operation of the hydraulic motor depicted in FlGS. 2 and 8, rotor40 is driven in a counterclockwise direction, whereby abutment valvescomponents 74 and 76 are rotated clockwise by the meshing engagement ofrotor gear 68 with the corresponding abutment valve gear 100. Theabutment valve diameters, as mentioned hereinbefore, are each two-thirdsthe hub diameter of the rotor, and the gear ratio between rotor gear 68and an abutment valve gears 100 provides for the abutment valves to berotated one-half faster in rpm than the rotor. Further, the rotor andabutment valves are interrelated for the relative rotation therebetweento provide for a lobe of one or the other of the abutment valves toalways be in sealing engagement with the rotor hub, and for a recess ofthe other abutment valve to be positioned to receive a lobe of therotor. As illustrated in FIGS. 2 and 8 of the drawing, the rotor andabutment valve components are in an operative position thereof in whicha lobe of abutment valve 76 sealingly engages the rotor hub and a recessof abutment valve 74 receives lobe 1l2b of rotor 40. The cylindricallobe surfaces of the abutment valves have a circumferential dimensioncorresponding substantially to the circumferential dimension of sealingplate 152 between adjacent lobes of rotor 40.

With reference now to FIG. 8 in particular, the rotor hub and abutmentvalve lobe sealing relationship will be described in detail. Sealingengagement between the abutment valve lobe and plate 152 is always alonga line between rotor axis A and the corresponding abutment valve axiswhich in this instance is axis C of abutment valve 76. The line ofsealing engagement is designated X in FIG. 8. When the rotor andabutment valve are relatively positioned for initial sealing engagementbetween abutment valve surface 120 and plate 152, end 120a of surface120 engages plate end surface 1580 at line X, whereby plate opening 1620at end 154 of the plate is opened to high pressure fluid entering inletpassage 122. Accordingly, hydraulic fluid under pressure enters hubrecess 164a adjacent end 154 of plate 152 and biases the correspondingpin 166 radially outwardly against the inner surface of plate 152 and awall of the recess, as illustrated in FIG. 8. The hydraulic force on pin166 biases plate 152 against surface 120 of abutment valve lobe 11611 toeffectively seal against leakage of high pressure fluid between theplate and valve in a direction opposite to the direction of rotation ofrotor 40. The position of pin 166 in recess 164a blocks the flow of highpressure fluid to the next adjacent recess l64b until such time asrelative rotation between the rotor and abutment valve so positionsplate 152 and abutment valve surface 120 that plate opening 162b isuncovered and thus opened to the high pressure fluid entering inletpassage 122. Hydraulic fluid under pressure then enters passage 1162band hub recess 16% vto bias the corresponding pin 166 radially outwardlyagainst plate 152 and a wall of recess 164b to bias plate 152 radiallyoutwardly into sealing engagement with abutment valve surface-120. Atthe same time, fluid under pressure flows through passage 162b intorecess 164a, whereby the fluid pressure against pin 166 in recess 164ais equalized and the latter pin no longer is forced against plate 152.Rotor and abutment valve rotation then brings these components to theposition illustrated in FIG. 8, wherein opening 1620 is exposed to highpressure fluid for the fluid to enter hub recess 164C to bias thecorresponding pin 166 radially outwardly as described hereinabove andfor the pressure against pin 166 in recess 16% to be equalized. It willbe noted that the next adjacent plate opening 162d is closed by surfaceof the abutment valve, whereby fluid under pressure can not flowtherethrough into hub recess 164d at this time. This relationship existsbetween each of the plate openings beginning with opening 162b whensealing engagement between the rotor hub and abutment valve isinitiated. End opening 162a, however, is not so closed, whereby sealingengagement between plate end 158a and end 120a of abutment valve surface120 is established immediately upon movement of these surfaces intoengagement at the beginning of the sealing operation. Continued rotationof the rotor and abutment components from the positions illustrated inFIG. 8 causes plate opening 162d to be uncovered for flow of hydraulicfluid under pressure into recess 164d for the corresponding pin 166 tobe radially biased outwardly against plate 152 to maintain sealingengagement between the plate and abutment valves surface. Again, fluidflow into recess 164c relieves the bias on the corresponding pin. Thissequential uncovering of the plate openings and the resulting biasingand release of the pins in the adjacent hub recesses continues until end1201) of surface 120 engages with end 158b of plate 152.

At the moment when end 12% of surface 120 and end 1581) of plate 152move out of sealing engagement, the rotor and abutment valves arerelatively positioned for the trailing lobe l12b of the rotor in FIG. 8to enter the recess in abutment valve 76 behind end surface 12Gbthereof, and for lobe end surface 120a of a abutment valve 74 to engagethe end surface of the sealing plate 152 between rotor lobes ll2b and1120. Sealing engagement relationship between a lobe of abutment valve74 and sealing plate 152 between rotor lobes 112b and 112C is thusestablished and is maintained in the manner described above with regardto the sealing between lobe 116a of abutment valve 76 and plate 152between rotor lobes 112a and 112b. The point of sealing engagementbetween the rotor hub and abutment valve 74 is along a line designated Yin FIG. 2 and extending between rotor axis A and abutment valve axis BWhen sealing engagement between the lobe of abutment valve 74 and plate152 between rotor lobes 11212 and 112C terminates as a result of therotation of the rotor and abutment valves, plate 152 between rotor lobes1l2b and 112C moves into sealing relationship with lobe l16b of abutmentvalve 76. Accordingly, it will be appreciated that the rotor andabutment valve components are continuously sealed against leakage ofhigh pressure fluid therebetween in a direction opposite the directionof rotation of the rotor during operation of the hydraulic motor. Theparticular hydraulically actuated seal arrangement provides for bettersealing engagement between the rotor and abutment valve components thanheretofore possible, whereby fluid leakage of the character sealedagainst is appreciably reduced to increase motor efficiency. Further,

the rotation of the abutment valve components onehalf faster in rpm thanthe rotor, together with the relative diameters of the outer surface ofthe abutment valve and the outer surface of the rotor hub as defined bysealing plates 152, provides for rolling contact between the sealingplates and cylindrical abutment valve surfaces to take place in a mannerwhereby plates 152 tend to drive the abutment valve. This driving actioneliminates back lash between the rotor and abutment valve gears.

While the configuration of the hub recesses 16411-f in cross section canvary, preferably the side walls of the recesses are inclined at anincluded angle of 45 relative to a radial axis through the bottom of therecess. This provides for the biasing force of the hydraulic fluid to beapplied to pins tee in a manner whereby the pressure engagement of thepins against the side wall of the recess and the inner surface of plate152 is substantially equal. Such equal pressure engagement best assuresagainst leakage of fluid between the pin and recess wall and between thepin and plate 152. Further, the 45 included angle provides for aradially outward force to be applied by the pins against plate 152 whileachieving the desired sealing engagement between the pins, recess walland seal plate. In this respect, if the incline of the recess wall istoo great, the radial force of the pin against plate 152 is increased,thus increasing the sealing pressure between the plate and abutmentvalve lobe. On the other hand, if the incline of the recess wall iseliminated then there will be places where the plate 152 is inadequatelybiased into sealing engagement with the abutment valve lobe. While the45 included angle provides the best sealing relationship and radial pinforce combination, other angles can be employed without departing fromthe principles of the seal arrangement. It should be noted too that itis only necessary to incline the wall of the recess which is thetrailing wall with respect to the direction of rotation of the rotor.lnclining both walls advantageously provides for the motor to beoperated in either direction of rotation which, of course, is mostdesirable. Further, the radial depth of the recesses and the diameter ofthe pins as well as the number of recesses employed can be varied, itonly being necessary to provide sufficient clearance between the pinsand the bottom of the recess to permit the hydraulic fluid to flowtherebetween.

ABUTMENT VALVE SHAFT SEAL In accordance with yet another aspect of thepresent invention, internal fluid leakage axially along outer portionsof the abutment valve support shafts is effectively reduced to furtherincrease motor efficiency. In this respect, as mentioned hereinabove,the opposite ends of each of the abutment valve shafts is provided witha bearing and seal arrangement designated generally by numeral 88disposed about the corresponding abutment valve shaft portion andbetween the shaft and a cooperative recess or opening in the housing forthe shaft portion. The abutment valve shaft bearing and sealingarrangements are identical, and accordingly, only one of thearrangements will be described in detail. In this respect, the sealarrangement between shaft portion 90 of abutment valve 74 and wallportion 98 of housing member 12, illustrated in FIGS. 3 and 5, will bedescribed. Shaft portion 90 includes a first portion 180 extendingaxially from cylindrical disc portion 182 adjacent the corresponding endof the abutment valve body. Shaft portion further includes a terminalportion 184 of smaller .diameter than portion and extending through anopening in wall 98 and into the gear chamber as described hereinabove.Wall 98 of housing includes an entrance portion I86 opening from theabutment valve chamber side thereof and a second portion 188 of smallerdiameter extending axially from entrance portion 186 and opening intothe gear chamber. The abutment valve side of housing wall 98 is a highpressure area into which operating fluid under pressure leaks from theabutment valve chamber, and the gear chamber is a low pressure area,whereby a pressure drop exists across wall portion 98. The area alongshaft portion 184 between the high and low pressure sides of wall 98defines a relatively short fluid leakage path. Considerable fluidleakage can result in this area due to the shortness of the leakage pathand the pressure differential across the housing wall. Heretofore,efforts to reduce the fluid leakage between components of devices of thecharacter of the present invention has involved the precision machiningof bearing components and shafts, the use of elaborate sealarrangements, or structural arrangements intended to lengthen theleakage path in an effort to reduce the amount of leakage. The previousdesigns are reasonably expensive, often result in creating undesirablebearing loads and reducing bearing life and, moreover, are not aseffective as desired with regard to lessening the degree of leakage.

In accordance with the present invention, a bearing and seal arrangementis provided which is of a floating character, whereby the degree ofprecision required in machining the various components is reduced,bearing life is increased and deliterious bearing loads are minirnized.Further, while the leakage path is quite short the bearing and sealassembly is responsive to fluid pressure on the high pressure side ofthe housing wall to increase sealing engagement between components ofthe seal assembly in a manner whereby leakage across the housing wall issubstantially eliminated. More particularly, in this respect, thebearing and seal arrangement of the present invention includes a steppedbearing component 190 of sintered bearing bronze, or the like, in theform of a sleeve having a cylindrical inner surface 192 surrounding andsealing engaging the outer surface of shaft portion 184 and a radialface 193 engaging end face 180a of abutment valve shaft portion 180. Theradially outer surface of bearing 1% is stepped to define a flangeportion 194 having a load face 194a engaging the high pressure face 98aof housing wall 98. The stepped bearing 1% further includes a sleeveportion 196 in the circumferential space between shaft portion 184 andportion 188 of the opening through wall 98, and a shoulder portion 198intermediate flange portion 194 and sleeve portion 196. Sleeve portion196 is of smaller diameter than portion 188 of the opening through wall98 to provide a radial clearance space 189 therebetween. Shoulderportion 198 extends axially into the entrance end 186 of the opening inwall 98 and terminates therein in axially spaced relationship withrespect to wall 200 defining the inner end of entrance portion 186.Further, shoulder portion 198 has a diameter slightly less than thediameter of the entrance portion of the recess 186, thus to define acircumferential space 202 between the shoulder portion and recess 186.

A resilient O-ring seal 204 and a back-up ring 206 are disposed in thecircumferential chamber defined by wall 200 and the opposed wall portion198a of shoulder 198 of the bearing to seal against fluid leakagebetween the bearing and the opening through wall 98, as set forth morefully hereinafter. When the abutment valve chamber is pressurized backup ring 206 will be pushed against wall 200. Further, radial face 193 ofbearing element 190 disposed against ene face 180a of shaft portion 180of the abutment valve is provided with a diametric extending recess 208defining a pair of fluid passageways in communication at their radialouter ends with high pressure fluid flowing axially along abutment valvebearing 94 and communicating at their radial inner ends with the outersurface of shaft portion 194.

Bearing 190 is a floating bearing in that clearance spaces 189 and 202permit radial or transverse movement of the bearing relative to wall 98in response to corresponding movement of the abutment valve shaft. Thisarrangement advantageously provides for sealing without the bearingsleeve 190 taking heavy loads. Each clearance 189 and 202 is greaterthan the clearance between the abutment valve shaft and its main supportbearing 94. The bearing load on the sleeve 190 is thus determined byfriction between faces 194a and 98a. Recess 208 in bearing 190 permitshydraulic fluid under pressure to exert an axial force against sleeve190 to maintain flange 194 against wall face 98a at all imes duringmotor operation. Sealing element 204 is, of course, disposed betweensleeve 190 and the opening through wall 98 under a degree of radialcompression which prevents any fluid leakage therepast. It will beappreciated, therefore, that by providing for the shaft portion to besupported and sealed by a floating bearing and seal arrangement, lessaccuracy in machining in the sealing areas between the components of theassembly is required, thus decreasing manufacturing expenses, and at thesame time a more effective seal is achieved than heretofore possiblewhereby fluid leakage is substantially eliminated to further increasethe efficiency of motor operation.

in order to maintain a balance in the fluid pressure acting against thebearing and seal arrangements at opposite ends of the abutment valves,the abutment valves are provided with longitudinally extending fluidpassageways 212 extending through the lobed portions thereof.Passageways 212 provide for the opposite ends of the abutment valveshafts to be maintained in fluid communication.

it will be appreciated, of course, that a certain amount of fluidleakage will occur along the shaft portions at the opposite ends of theabutment valve components. The fluid leakage occurring along the shaftportion at the end opposite the end associated with the housing wall 98can be delivered to bearing assembly 48 at the corresponding end of themotor by a passageway 214 opening into the bearing recess from shaftrecess 86 adjacent shaft portion 84, as illustrated in FIG. 3. Leakagealong the shaft portion extending through housing wall 98 can be drainedor returned to the sump area by means of an appropriate passage 216 inthe motor housing.

From the foregoing description of a preferred embodiment of the presentinvention, it will be appreciated that in accordance with the presentinvention a positive displacement device for hydraulic fluid is providedcomprising a unique rotor and abutment valve combination wherein therotor has three lobes and the abutment valves each have two lobesoperatively interrelated therewith whereby the device is operable toprovide a low speed high torque hydraulic motor which is physicallycompact, inexpensive to manufacture and maintain and has improvedoperating characteristics. It will be appreciated further that inaccordance with the present invention a positive displacement device forfluids is provided having improved internal fluid sealingcharacteristics by which efficiency in operation of the device isachieved and which includes a new and improved rotor lobe and chamberseal arrangement, a new and improved rotor abutment valve sealarrangement and a new and improved abutment valve shaft bearing and sealarrangement. While the rotor of the hydraulic motor is described hereinas being driven in only one direction, it will be appreciated that themotor is operable in either direction merely by reversing the fluidinlet and outlet ports. Further, it will be appreciated that the crosssectional contours of the abutment valve recesses and rotor lobes can bevaried from the specific configurations illustrated without departingfrom the principles of the present invention.

Still further, it will be appreciated that the number of recesses andpins provided in the rotor hub between adjacent lobes thereof forbiasing the sealing plate against the abutment valve lobes can be variedand is not limited to the specific number illustrated and described inconjunction with the preferred embodiment. Moreover, while it ispreferred that the fluid passages for the recesses be defined byopenings through the sealing plate, it will be appreciated that fluidcould otherwise be delivered to the recesses, such as by valvedpassageways leading to the recesses, for example. Many modifications ofthe various structural relationships described herein will be suggestedto those skilled in the art upon reading the foregoing description, andsuch modifications can readily be employed without departing from theprinciples of the present invention.

Further, as mentioned hereinbefore, while the three lobe-two lobeconcept with the abutment valve axes spaced 60 is preferred for ahydraulic motor, a four lobe-two lobe arrangement with abutment valveaxes spaced 45 is preferred for a hydraulic pump. The latter arrangementis schematically illustrated in FIG. 9 wherein it will be seen that therotor 300 is provided with four rotor lobes 302 spaced apart equidistantcircumferentially of the rotor axis, whereby adjacent lobes are spacedapart in accordance with the present invention, the two two lobedabutment valves 304 have their axes circumferentially spaced apartonehalf the angular distance between adjacent rotor lobes, and,accordingly, the abutment valve axes are spaced apart 45. In addition tothe advantages described hereinabove with regard to a three lobe-twolobe arrangement, the four lobe-two lobe arrangement advantageouslyenables further increasing the inlet and outlet port areas to increasethe fluid displacement capability for a pump.

As many possible embodiments of the present invention may be made and asmany possible changes may be made in the embodiment herein described, itis to be distinctly understood that the foregoing descriptive matter isto be interpreted merely as illustrative of the present invention andnot as a limitation.

Having thus described my invention, l claim:

1. A positive displacement device for fluids comprising housing meanshaving rotor and abutment valve chambers, said rotor chamber includingan arcuate wall and said abutment valve chamber including a circularwall intersecting said rotor chamber wall, cooperable rotatable rotorand abutment valve members disposed respectively in said rotor andabutment valve chambers, fluid inlet and outlet ports at spacedlocations about said rotor chamber wall and opening axially into saidrotor chamber, said rotor comprising a hub and at least one lobeprojecting radially outwardly from said hub, said lobe having an outerend provided with a longitudinally extending recess opening radiallyoutwardly of said end, a sealing pin in said recess, said recess openinghaving a circumferential width less than the diameter of said pin, saidouter end of said lobe and said rotor chamber wall being radially spacedsuch that said recess communicates with said rotor chamber when said pinengages said rotor chamber wall for fluid under pressure to enter saidrecess from said rotor chamber, said outlet port having an end disposedin the path of movement of said recess for communicating said outletport with said recess to reduce the fluid pressure behind said rotorlobe prior to movement of said rotor lobe past said end of said outletport.

2. A positive displacement device for fluids comprising a housing havinga rotor chamber and a pair of abutment valve chambers therein, saidrotor chamber having an arcuate wall and said abutment valve chamberseach having a circular wall intersecting the rotor chamber wall, a rotorin said rotor chamber having a hub portion and three rotor lobes spacedequidistant thereabout and extending radially therefrom, an abutmentvalve in each of said abutment valve chambers each includingdiametrically opposed pairs of lobes and recesses, said abutment valvelobes having outer ends sealingly engagable with the rotor hub betweenadjacent rotor lobes, fluid inlet and outlet passages opening into saidrotor chamber at spaced locations about said rotor chamber wall, meansinterconnecting said rotor and abutment valves for simultaneous rotationin their respective chambers, and fluid pressure responsive seal meansbetween said abutment valve lobes and said rotor hub, said seal meansincluding sealing elements between adjacent rotor lobes and carried bysaid rotor for movement therewith and radial displacement relativethereto, means between said rotor hub and sealing elements fordisplacing said sealing elements outwardly of said rotor hub, saidsealing elements carried by said rotor including radially displaceablesealing plates extending between adjacent rotor lobes, and said meansfor displacing said sealing elements including at least one platebiasing member between each plate and the rotor hub, said biasing memberbeing movable radially outwardly with respect to said rotor hub todisplace said sealing plate radially outwardly.

3. A positive displacement device for fluids comprising housing meanshaving respective chambers therein for cooperably lobed rotor andabutment valve members, bearing means supporting said rotor and abutmentvalve members for rotation in their respective chambers, said abutmentvalve members including corresponding shaft portions extending intoshaft openings therefor in wall means of said housing means, and sealmeans between at least one of said abutment valve shaft portions and thecorresponding opening therefor, said seal means including a floatingbearing sleeve between said one abutment valve shaft portion andopening, said sleeve having an outer surface within and radially spacedfrom the inner surface of said opening and an inner surface inengagement with said one shaft portion to provide controlled leakagealong said one shaft portion, and an annular seal element radiallycompressed in the space between said sleeve and opening, said housingwall means having a surface facing said chambers and said bearing sleevebeing rotatably, radially and axially displaceable relative to said wallmeans, said sleeve including a radial load face engaging said wallsurface and an axially opposed fluid pressure surface facing thecorresponding abutment valve chamber and exposed to fluid under pressuretherein for maintaining said load face in engagement with said wallsurface, said sleeve further including a second radial face disposedaxially inwardly of said opening, means in said opening defining anabutment axially spaced from said second radial face, said annular sealelement being disposed in the space between said second radial face andsaid abutment.

4. A positive displacement device for fluids comprising housing meanshaving high fluid pressure and low fluid pressure zones therein, chambermeans in said high pressure zone and including rotor and abutment valvechambers for cooperatively lobed rotatable rotor and abutment valvemembers, bearing means supporting said abutment valve member forrotation, said housing means including a wall between said high and lowpressure zones, shaft means for said abutment valve member, said wallincluding an opening through which at least a portion of said shaftmeans extends and defining a leakage path for fluid from said highpressure zone to said low pressure zone, and floating bearing and sealmeans between said wall and said portion of said shaft means for sealingsaid leakage path, said bearing and seal means including a sleevebearing on said portion of said shaft means and between said portion ofsaid shaft means and said opening, said sleeve bearing having an innersurface engaging said shaft portion to provide controlled leakage alongsaid shaft portion between said high and low pressure zones, said sleevehaving an outer surface within said opening and radially spaced from theinner surface of said opening, a resilient seal element radiallycompressed between said outer surface of said sleeve bearing and saidinner surface of said opening, one end of said sleeve bearing includinga radial load face engaging the surface of said wall about said openingon the high pressure side of said wall, said one end of said sleevefurther including a fluid pressure surface axially opposed with respectto said load surface and exposed to fluid under pressure in said highpressure zone for said high pressure fluid to press said load surfaceagainst said wall surface.

5. The positive displacement device of claim 4, said sleeve bearingfurther including a radial shoulder within said opening, an opposedshoulder in said opening spaced from said radial shoulder, and saidresilient seal element being disposed between said shoulders.

6. A hydraulic, rotary abutment motor or pump comprising a housinghaving a rotor chamber and a pair of abutment valve chambers therein,said rotor chamber having an arcuate wall and said abutment valvechambers each having a circular wall intersecting the rotor chambervwall, a rotor in said rotor chamber having a hub portion and three rotorlobes spaced substantially equidistant thereabout and extending radiallytherefrom, an abutment valve in each of said abutment valve chamberseach including substantially diametrically opposed pairs of lobes andrecesses, said abutment valve lobes having outer ends sealinglyengageable with the rotor hub between adjacent rotor lobes, thecircumferential angle between the axes of said abutment valves beingsubstantially 60, fluid inlet and outlet passages opening into saidrotor chamber at spaced locations about said rotor chamber wall, andmeans interconnecting said rotor and abutment valves for simultaneousrotation in their respective chambers, fluid pressure responsive sealmeans between said rotor lobes and rotor chamber wall, said seal meansincluding a sealing element carried by each of said rotor lobes formovement therewith and radially outward displacement relative thereto,said sealing element being a cylindrical pin extending longitudinally ofsaid rotor lobe, said rotor lobe including a longitudinal recess opentoward said rotor chamber wall, and said pin being disposed in saidrecess for radially outward displacement relative thereto and intoengagement with said rotor chamber wall, said opening into said loberecess being circumferentially narrower than the diameter of said pin,said rotor chamber wall including a circular portion between said inletand outlet passages having a radius of curvature relative to the rotorchamber axis less than the maximum radial dimension along said rotorlobe to the outermost point of said pin in said lobe recess, and saidrotor chamber wall including a lead-in portion at each end of saidcircular portion and having one end merging with the corresponding endof said circular portion and another end radially spaced from said axisa distance greater than said maximum radial dimension.

7. A positive displacement device for fluids comprising, housing meanshaving rotor and abutment valve chambers, said rotor chamber having anarcuate wall and said abutment valve chamber having a circular wallintersecting with said rotor chamber wall, rotatable rotor and abutmentvalve members disposed respectively in said rotor and abutment valvechambers, fluid inlet and outlet openings at spaced locations about saidrotor chamber wall, said rotor and abutment valve including cooperablemeans therebetween for sealing against fluid flow from said inlet tosaid outlet between said rotor and abutment valve, said cooperable meansincluding fluid pressure actuated sealing means on said rotor and a lobesurface on said abutment valve sealingly engagable withsaid sealingmeans, said sealing means including plate means carried by said rotor,fluid actuated means for displacing said plate means radially outwardlyof said rotor toward said lobe surface, and means for directing fluidflow to said fluid actuated means, said rotor including a hub and saidplate means overlying said hub, said fluid actuated means includingpressure applying elements between said hub and plate means anddisplacable radially outwardly of said hub to displace said plate meansinto sealing engagement with said lobe surface.

8. The positive displacement device of claim 7, wherein said plate meansand lobe surface are relatively movable in progressive engagement andsaid fluid actuated means is operable to sequentially displace saidpressure applying elements for said plate means to sealingly engage saidlobe surface progressively during said movement.

The positive displacement device of claim 8, wherein said pressureapplyirig' elements are pins extending longitudinally of said rotor incorresponding longitudinally extending recesses opening toward saidplate means, and said plate means includes passageway means for fluidunder pressure to enter said recesses sequentially to displace said pinsinto engagement with said plate means.

10. The positive displacement device of claim 9, wherein saidlongitudinally extending recesses each include a side wall having aplane intersecting the plane of said plate means at an interior angleless than said pins being cylindrical and having line contact with saidside wall of the corresponding recess and with said plate means when inpressure engagement with said plate means.

11. A hydraulic motor comprising housing means having an arcuate rotorchamber and fluid inlet and outlet passages spaced circumferentiallyabout said chamber, a rotor disposed in said chamber for rotation in agiven direction relative to the chamber axis and being rotatable in saidgiven direction by fluid under pressure entering said chamber throughsaid inlet passage, output means operatively associated with said rotorand driven in response to rotation of said rotor, said housing includingcircular abutment valve chambers parallel with and opening into saidrotor chamber, an abutment valve rotatably mounted in each of saidabutment valve chambers, said rotor having three radially projectingdisplacement lobes and said abutment valves each having two radiallydirected sealing lobes engagable with said rotor between adjacentdisplacement lobes thereof during rotation of said rotor in said givendireciton to seal against fluid flow from said inlet passage toward saidoutlet passage in a direction opposite said given direction, andradially outwardly displacable sealing means carried by said rotorbetween said displacement lobes for sealing engagement with saidabutment valve sealing lobes, said radially outwardly displacablesealing means including plate means extending circumferentially betweenadjacent displacement lobes and fluid actuated pressure applyingelements radially inwardly of said plate means for displacing said platemeans toward said abutment valve sealing lobes.

12. The hydraulic motor of claim 11, wherein said rotor includes a hubportion between said adjacent displacement lobes and said pressureapplying means includes cylindrical pins disposed in correspondinglongitudinally extending recesses in said hub portion, said plate meansincluding fluid passageways opening between said recesses and the outersurface of said plate means.

13. The hydraulic motor of claim 12, wherein said recesses in said hubportion include a plurality of parallel spaced apart recesses having atleast one wall thereof inclined relative to said plate means, said fluidpassageways in said plate means including at least one openingcommunicating with each recess for flow of fluid under pressurethereinto.

14. The hydraulic motor of claim 12, wherein said sealing lobes have anouter surface movable in progressive engagement circumferentially acrosssaid plate means during rotation of said rotor in said given direction,said openings to said recesses being arranged in circumferentiallyspaced relation along said plate means and being sequentially uncoveredby movement of said lobe outer surface across said plate-means for saidfluid under pressure to enter said recesses sequentially during saidmovement 15. A positive displacement device for fluids comprisinghousing means having rotor and abutment valve chambers, said rotorchamber including an arcuate wall and said abutment valve chamberincluding a circular wall intersecting said rotor chamber wall,cooperable rotatable rotor and abutment valve chambers, fluid inlet andoulet ports at spaced locations about said rotor chamber wall, saidrotor comprising a hub and at least two lobes projecting radiallyoutwardly from said hub, and fluid pressure actuated sealing meanscarried by said lobes and displaceable radially outwardly relativethereto for sealing engagemnet with said rotor chamber wall, said rotorchamber wall including a circular portion between said inlet and outletports and having a given radius with respect to the axis of said rotorchamber, said chamber wall further including a second portion adjacentsaid outlet port and merging with the corresponding end of said circularportion and divering with respect to said chamber axis, said sealingmeans in moving from said inlet port toward said outlet port engagingsaid second portion of said rotor chamber wall ahead of said outlet portto reduce the fluid pressure behind the corresponding one of said rotorlobes.

16. The positive displacement of claim 15, wherein said lobe has anouter end provided with a longitudinal extending recess opening radiallyoutwardly of said end, and said sealing means includes a sealing elementdisposed in said recess and displacable outwardly of said recess openingfor sealing engagement with said rotor chamber wall in response to fluidunder pressure acting thereagainst in said recess.

17. The positive displacement device of claim 16,

wherein said sealing element is a metal pin and said re cess opening hasa circumferential width less than the diameter of said pin, said outerend of said lobe and said rotor chamber wall being radially spaced suchthat said recess communicates with said rotor chamber when said pinengages said rotor chamber wall for fluid under pressure to enter saidrecess from said rotor chamber.

18. The positive displacement device of claim 17, wherein said recessincludes opposed longitudinally extending side walls diverging inwardlyfrom said recess

1. A positive displacement device for fluids comprising housing meanshaving rotor and abutment valve chambers, said rotor chamber includingan arcuate wall and said abutment valve chamber including a circularwall intersecting said rotor chamber wall, cooperable rotatable rotorand abutment valve members disposed respectively iN said rotor andabutment valve chambers, fluid inlet and outlet ports at spacedlocations about said rotor chamber wall and opening axially into saidrotor chamber, said rotor comprising a hub and at least one lobeprojecting radially outwardly from said hub, said lobe having an outerend provided with a longitudinally extending recess opening radiallyoutwardly of said end, a sealing pin in said recess, said recess openinghaving a circumferential width less than the diameter of said pin, saidouter end of said lobe and said rotor chamber wall being radially spacedsuch that said recess communicates with said rotor chamber when said pinengages said rotor chamber wall for fluid under pressure to enter saidrecess from said rotor chamber, said outlet port having an end disposedin the path of movement of said recess for communicating said outletport with said recess to reduce the fluid pressure behind said rotorlobe prior to movement of said rotor lobe past said end of said outletport.
 2. A positive displacement device for fluids comprising a housinghaving a rotor chamber and a pair of abutment valve chambers therein,said rotor chamber having an arcuate wall and said abutment valvechambers each having a circular wall intersecting the rotor chamberwall, a rotor in said rotor chamber having a hub portion and three rotorlobes spaced equidistant thereabout and extending radially therefrom, anabutment valve in each of said abutment valve chambers each includingdiametrically opposed pairs of lobes and recesses, said abutment valvelobes having outer ends sealingly engagable with the rotor hub betweenadjacent rotor lobes, fluid inlet and outlet passages opening into saidrotor chamber at spaced locations about said rotor chamber wall, meansinterconnecting said rotor and abutment valves for simultaneous rotationin their respective chambers, and fluid pressure responsive seal meansbetween said abutment valve lobes and said rotor hub, said seal meansincluding sealing elements between adjacent rotor lobes and carried bysaid rotor for movement therewith and radial displacement relativethereto, means between said rotor hub and sealing elements fordisplacing said sealing elements outwardly of said rotor hub, saidsealing elements carried by said rotor including radially displaceablesealing plates extending between adjacent rotor lobes, and said meansfor displacing said sealing elements including at least one platebiasing member between each plate and the rotor hub, said biasing memberbeing movable radially outwardly with respect to said rotor hub todisplace said sealing plate radially outwardly.
 3. A positivedisplacement device for fluids comprising housing means havingrespective chambers therein for cooperably lobed rotor and abutmentvalve members, bearing means supporting said rotor and abutment valvemembers for rotation in their respective chambers, said abutment valvemembers including corresponding shaft portions extending into shaftopenings therefor in wall means of said housing means, and seal meansbetween at least one of said abutment valve shaft portions and thecorresponding opening therefor, said seal means including a floatingbearing sleeve between said one abutment valve shaft portion andopening, said sleeve having an outer surface within and radially spacedfrom the inner surface of said opening and an inner surface inengagement with said one shaft portion to provide controlled leakagealong said one shaft portion, and an annular seal element radiallycompressed in the space between said sleeve and opening, said housingwall means having a surface facing said chambers and said bearing sleevebeing rotatably, radially and axially displaceable relative to said wallmeans, said sleeve including a radial load face engaging said wallsurface and an axially opposed fluid pressure surface facing thecorresponding abutment valve chamber and exposed to fluid under pressuretherein for maintaining said load face in engagement with said wallsurface, saiD sleeve further including a second radial face disposedaxially inwardly of said opening, means in said opening defining anabutment axially spaced from said second radial face, said annular sealelement being disposed in the space between said second radial face andsaid abutment.
 4. A positive displacement device for fluids comprisinghousing means having high fluid pressure and low fluid pressure zonestherein, chamber means in said high pressure zone and including rotorand abutment valve chambers for cooperatively lobed rotatable rotor andabutment valve members, bearing means supporting said abutment valvemember for rotation, said housing means including a wall between saidhigh and low pressure zones, shaft means for said abutment valve member,said wall including an opening through which at least a portion of saidshaft means extends and defining a leakage path for fluid from said highpressure zone to said low pressure zone, and floating bearing and sealmeans between said wall and said portion of said shaft means for sealingsaid leakage path, said bearing and seal means including a sleevebearing on said portion of said shaft means and between said portion ofsaid shaft means and said opening, said sleeve bearing having an innersurface engaging said shaft portion to provide controlled leakage alongsaid shaft portion between said high and low pressure zones, said sleevehaving an outer surface within said opening and radially spaced from theinner surface of said opening, a resilient seal element radiallycompressed between said outer surface of said sleeve bearing and saidinner surface of said opening, one end of said sleeve bearing includinga radial load face engaging the surface of said wall about said openingon the high pressure side of said wall, said one end of said sleevefurther including a fluid pressure surface axially opposed with respectto said load surface and exposed to fluid under pressure in said highpressure zone for said high pressure fluid to press said load surfaceagainst said wall surface.
 5. The positive displacement device of claim4, said sleeve bearing further including a radial shoulder within saidopening, an opposed shoulder in said opening spaced from said radialshoulder, and said resilient seal element being disposed between saidshoulders.
 6. A hydraulic, rotary abutment motor or pump comprising ahousing having a rotor chamber and a pair of abutment valve chamberstherein, said rotor chamber having an arcuate wall and said abutmentvalve chambers each having a circular wall intersecting the rotorchamber wall, a rotor in said rotor chamber having a hub portion andthree rotor lobes spaced substantially equidistant thereabout andextending radially therefrom, an abutment valve in each of said abutmentvalve chambers each including substantially diametrically opposed pairsof lobes and recesses, said abutment valve lobes having outer endssealingly engageable with the rotor hub between adjacent rotor lobes,the circumferential angle between the axes of said abutment valves beingsubstantially 60*, fluid inlet and outlet passages opening into saidrotor chamber at spaced locations about said rotor chamber wall, andmeans interconnecting said rotor and abutment valves for simultaneousrotation in their respective chambers, fluid pressure responsive sealmeans between said rotor lobes and rotor chamber wall, said seal meansincluding a sealing element carried by each of said rotor lobes formovement therewith and radially outward displacement relative thereto,said sealing element being a cylindrical pin extending longitudinally ofsaid rotor lobe, said rotor lobe including a longitudinal recess opentoward said rotor chamber wall, and said pin being disposed in saidrecess for radially outward displacement relative thereto and intoengagement with said rotor chamber wall, said opening into said loberecess being circumferentially narrower than the diameter of said pin,said rotor chamber wall including a circUlar portion between said inletand outlet passages having a radius of curvature relative to the rotorchamber axis less than the maximum radial dimension along said rotorlobe to the outermost point of said pin in said lobe recess, and saidrotor chamber wall including a lead-in portion at each end of saidcircular portion and having one end merging with the corresponding endof said circular portion and another end radially spaced from said axisa distance greater than said maximum radial dimension.
 7. A positivedisplacement device for fluids comprising, housing means having rotorand abutment valve chambers, said rotor chamber having an arcuate walland said abutment valve chamber having a circular wall intersecting withsaid rotor chamber wall, rotatable rotor and abutment valve membersdisposed respectively in said rotor and abutment valve chambers, fluidinlet and outlet openings at spaced locations about said rotor chamberwall, said rotor and abutment valve including cooperable meanstherebetween for sealing against fluid flow from said inlet to saidoutlet between said rotor and abutment valve, said cooperable meansincluding fluid pressure actuated sealing means on said rotor and a lobesurface on said abutment valve sealingly engagable with said sealingmeans, said sealing means including plate means carried by said rotor,fluid actuated means for displacing said plate means radially outwardlyof said rotor toward said lobe surface, and means for directing fluidflow to said fluid actuated means, said rotor including a hub and saidplate means overlying said hub, said fluid actuated means includingpressure applying elements between said hub and plate means anddisplacable radially outwardly of said hub to displace said plate meansinto sealing engagement with said lobe surface.
 8. The positivedisplacement device of claim 7, wherein said plate means and lobesurface are relatively movable in progressive engagement and said fluidactuated means is operable to sequentially displace said pressureapplying elements for said plate means to sealingly engage said lobesurface progressively during said movement.
 9. The positive displacementdevice of claim 7, wherein said pressure applying elements are pinsextending longitudinally of said rotor in corresponding longitudinallyextending recesses opening toward said plate means, and said plate meansincludes passageway means for fluid under pressure to enter saidrecesses sequentially to displace said pins into engagement with saidplate means.
 10. The positive displacement device of claim 9, whereinsaid longitudinally extending recesses each include a side wall having aplane intersecting the plane of said plate means at an interior angleless than 90*, said pins being cylindrical and having line contact withsaid side wall of the corresponding recess and with said plate meanswhen in pressure engagement with said plate means.
 11. A hydraulic motorcomprising housing means having an arcuate rotor chamber and fluid inletand outlet passages spaced circumferentially about said chamber, a rotordisposed in said chamber for rotation in a given direction relative tothe chamber axis and being rotatable in said given direction by fluidunder pressure entering said chamber through said inlet passage, outputmeans operatively associated with said rotor and driven in response torotation of said rotor, said housing including circular abutment valvechambers parallel with and opening into said rotor chamber, an abutmentvalve rotatably mounted in each of said abutment valve chambers, saidrotor having three radially projecting displacement lobes and saidabutment valves each having two radially directed sealing lobesengagable with said rotor between adjacent displacement lobes thereofduring rotation of said rotor in said given direciton to seal againstfluid flow from said inlet passage toward said outlet passage in adirection opposite said given direction, and radially outwardlydisplacable sealing means carried by said rOtor between saiddisplacement lobes for sealing engagement with said abutment valvesealing lobes, said radially outwardly displacable sealing meansincluding plate means extending circumferentially between adjacentdisplacement lobes and fluid actuated pressure applying elementsradially inwardly of said plate means for displacing said plate meanstoward said abutment valve sealing lobes.
 12. The hydraulic motor ofclaim 11, wherein said rotor includes a hub portion between saidadjacent displacement lobes and said pressure applying means includescylindrical pins disposed in corresponding longitudinally extendingrecesses in said hub portion, said plate means including fluidpassageways opening between said recesses and the outer surface of saidplate means.
 13. The hydraulic motor of claim 12, wherein said recessesin said hub portion include a plurality of parallel spaced apartrecesses having at least one wall thereof inclined relative to saidplate means, said fluid passageways in said plate means including atleast one opening communicating with each recess for flow of fluid underpressure thereinto.
 14. The hydraulic motor of claim 12, wherein saidsealing lobes have an outer surface movable in progressive engagementcircumferentially across said plate means during rotation of said rotorin said given direction, said openings to said recesses being arrangedin circumferentially spaced relation along said plate means and beingsequentially uncovered by movement of said lobe outer surface acrosssaid plate means for said fluid under pressure to enter said recessessequentially during said movement
 15. A positive displacement device forfluids comprising housing means having rotor and abutment valvechambers, said rotor chamber including an arcuate wall and said abutmentvalve chamber including a circular wall intersecting said rotor chamberwall, cooperable rotatable rotor and abutment valve chambers, fluidinlet and oulet ports at spaced locations about said rotor chamber wall,said rotor comprising a hub and at least two lobes projecting radiallyoutwardly from said hub, and fluid pressure actuated sealing meanscarried by said lobes and displaceable radially outwardly relativethereto for sealing engagemnet with said rotor chamber wall, said rotorchamber wall including a circular portion between said inlet and outletports and having a given radius with respect to the axis of said rotorchamber, said chamber wall further including a second portion adjacentsaid outlet port and merging with the corresponding end of said circularportion and divering with respect to said chamber axis, said sealingmeans in moving from said inlet port toward said outlet port engagingsaid second portion of said rotor chamber wall ahead of said outlet portto reduce the fluid pressure behind the corresponding one of said rotorlobes.
 16. The positive displacement of claim 15, wherein said lobe hasan outer end provided with a longitudinal extending recess openingradially outwardly of said end, and said sealing means includes asealing element disposed in said recess and displacable outwardly ofsaid recess opening for sealing engagement with said rotor chamber wallin response to fluid under pressure acting thereagainst in said recess.17. The positive displacement device of claim 16, wherein said sealingelement is a metal pin and said recess opening has a circumferentialwidth less than the diameter of said pin, said outer end of said lobeand said rotor chamber wall being radially spaced such that said recesscommunicates with said rotor chamber when said pin engages said rotorchamber wall for fluid under pressure to enter said recess from saidrotor chamber.
 18. The positive displacement device of claim 17, whereinsaid recess includes opposed longitudinally extending side wallsdiverging inwardly from said recess opening.